Preparation of lubricating oil



Patented Feb. 3, 1948 PREPARATION F LUBRICATING OIL Richard S. Vose,Swarthmore, Pa.,` assignor to Sun Oil Company, Philadelphia, Pa., acorporation of New Jersey Application February 19. 1944, serial No.523,050

The present invention relates to chemical re'- actions involvinghydrocarbons and more particularly to alkylation reactions wherebyhydrocarbons of lower molecular weight are converted into more valuablehydrocarbons of higher molecular weight. The invention is especiallyconcerned with the preparation of lubricating oil of high viscosityindex from composite hydrocarbon material of lower molecular Weighthaving poorer viscosity-temperature relationship.

The invention provides a process for convertin a composite hydrocarboncharge which may be gas oil or lubricating oil into lubricating oil ofgreater molecular weight and higher viscosity than the original charge.In accordance with the invention, the charge material is caused to reactwith a relatively high molecular Weight aliphatic alcohol in thepresence of a catalyst of the waterabsorbing type, whereby water issplit off from the reactants and the aliphatic radical from the alcoholis attached as a side chain to a hydrocarbon of the charge. This resultsin a product of higher paranicity than the charge, which accordingly hasa better viscosity-temperature relationship.

The process of the present invention is illustrated in the accompanyingdrawing in simple diagrammatic form. As shown in the drawing, charge oilis passed to a mixing or treating zone along with an aliphatic alcoholand a catalyst. The charge oil is preferably a distillate fraction andmay be any desired fraction above about 400 F., such as any gas oil orlubricating oil fraction, dependent on the particular product viscositydesired. The alcohol may be any desired aliphatic alcohol having atleast eight carbon atoms in the molecule` and preferentially is abranched chain alcohol having at least ten carbon atoms per molecule.Mixtures of alcohols also may be used. It is preferred that the chargeoil and alcohol be fed to the process in approximately molarproportions, although larger or smaller amounts of alcohol may be usedif desired. An amount of alcohol in excess of the molar proportionpermits a greater degree of alkylation but usually is not necessary forobtaining a product of high viscosity index. On the other handthe use ofalcohol in amount substantially less than the molar vproportion maylimit the degree of alkylation to such extent that the alkylated productwill have undesirably low viscosity index.

In the treating zone the reactants and catalyst are intimately mixeduntil no further amount of water is formed, thus indicating completionof the alkylation reaction, the time required depending on the degree ofmixing and the temperature employed in the treatment. Ordinary roomtemperatures such as 60-90 F. are suitable for carrying out the reactionalthough higher or lower temperatures also may be used successfully.Sufficient pressure is maintained in the treating 7 Claims. (Cl.26o-683.4)

zone to prevent vaporization of the catalyst at the temperatureemployed.

From the treating zone the reaction mixture is passed to a settling zonewherein oil-insoluble constituents comprising catalyst, water, alcoholnot consumed in the reaction and any sludge which may have formed, areseparated from the refined hydrocarbons. The oil-insoluble material isseparately withdrawn from the settling zone .andmay be subjected totreatment for recovery of the catalyst and alcohol. The renedhydrocarbon layer is then subjected to alkali treatment, for examplewith aqueous caustic soda, to neutralizev any retained catalyst, afterwhich it is washed and finally vdried to yield the desired lubricatingoil product. Y

-In practicing ,the above described process, it is distinctly preferableto utilize as charge to the process and oil fraction of low aromaticcontent, for example a fraction containing less than about 10 per centand preferably not more than about 5 per cent aromatic constituents. Ihave found that aromatics when present in higher concentration cause theformation of sludge or tar during. the alkylation reaction, which makesthe subsequent separation of oil-insoluble materials from the reactionmixture exceedingly difficult, whereas such difficulties are avoided ifthe' `.aromatic content of the charge is suciently low. A charge foilofsuitably low aromatic content may be prepared Iby solvent extraction,sulfuric acid treatment, selective adsorption by means of' granularadsorbents, or in any other desired manner.

As stated above, the catalyst utilized inthe process is of thewater-absorbing type. A preierred catalyst-is hydrofluoric acid inanhydrous or concentrated form. Other catalysts of the aforesaid typeare phosphoric acid, sulfuric acid, aluminum chloride and boronfluoride.

The following examples are illustrative and serve to show how theinvention may be carried out in actual practice:

Example I A gas oil derived from a, naphthenic base crude Wassolvent-extracted to reduce the aromatic content. One hundred parts byWeight .of the solvent-extracted oil was treated with 134 parts of abranched chain heptadecanol, specifically 3,9-diethyl-6-tridecanol, inthe presence of 157 parts anhydrous hydrogen uoride. The treatingtemperature was approximately F. and the reaction mixture was maintainedunder sufficient pressure to keep the hydrogen fluoride in liquid phase.After 14 hours of treatment during which continuous mixing was eiected,the reaction mixture Was permitted to stratify. The oil-insolublematerials were withdrawn and the refined hydrocarbon layer Wasneutralized with caustic soda, washed and dried, thereby yielding 191parts of MSM@ 3 alkylated product The following .tabulation showsproperties i"ofathe solverit extraetet sas oil and of the alkylatedproduct:

In place ot aliphatic alcohols, theiroorrespondl-mg-estersggchfioridesanijcifsuI-lat,esfznriayifbeV used in lkylating gasoil or lubricatingoil, although none of these agents is as satisfactory as the alcoholssolvent lkylatd' themselves mffce@ friuduct 1.1. 1 WhatsIf-Iclaimanddesire to protect by Letters G. o Patent is: A. P. I. gravity I ,3759? j'Th?. lilefhfd 'Of alkylating hydrocarbons Density 058318 '0.8188gimen-.comprisesreacting a hydrocarbon charge s U viscsitoy'at 100 F 33*200 10 boiling above about 400 F. contalnmg a substanv'iscsitymdex tss"y11120 tialfproportionf:ofnaphthenic constituents and Xfifgfl'rgggtfffn0' y containing less than about 10 percent aromatics Refractive index c.1 du 4552 With'atlea-sta substantlallyeguimola-r quantity G @Dqpecigdspesiggx'if. m 1;)2 of an allphatic alcohohcontammg at least 8car- `c 3mpogiiom v 15 lborratoms per moleculejunderalkylating-condi-V01. percentaromatics 55' .0 a f .L i f fvtfgsfsztafena; 9 b-pesenffwaiyt "i the la ,Avf'pfrfftnla E '54' `"8" 2.?The umethod Leo'fyalkylating hydrocarbons "e "eljfs 2.2 :Whichcomprisesreactingahydrocarboncharge "containing asubstantialproportionvof-naphth"envio l Weight per cent n aphthene rings. LW eight percentparanicohains. fl. Determined byfre'ezingfpoint-methudin benzenesolution.

`no `V`"sludge `ror tar lformeti 'durin'g the .lisa-lkylation treatment,and the'lsubsequentf' separation :ofthereact-ionfmixturerwasxeasilyaaccomplished, .When the originalunextra'ctedfgas oil, Awhich ha'd f an *constituents and"containinglless Nthan -'-abcut 10 f'p'er 'cent'faromatics withgat-least `a;"substan'tially lfequnnolarquantityofan-aliphaticf'alooholconl- In the presentexampletherewas'substantially 1.

-tracted z'lubricating oil :fraction zderived .rfrom tia Amixtuifeof-Gulf .-coastalcrudes-@wasfreactedwith taining at least ScarbonAatomsfper 'molecule under "alkylatng conditions f inthe presence o'f a:catalyst-ofthe'waterabsorbingitype 3.*'Themethod dei-'med' in'claim *1'wherein the cata'-1yst is hydrogenfiuorid'e.

4 9 unefmetndd w'definedinfclaimlfwhereinfthe 'alcohollsafbranche'dchain alcoholcontainingat vleast'l0-'carbonfatoms.Y."The"methodfdeneolv irrclaim '2"Whereinithe catalystis'lhydrogen'fluoride.

o5-parts f of :a branched z'chain'ftetradeeanol; spevcically2-methyle7-ethylsifundecanoL lin the :presencefof 91:.partsofeanhy'drous hydrogemu- ;oride, and under; conditions fsimi'lartoethose@used `in [Example- 1. After areaotiontimegof 9 1/2y hours,

the. reaction; mixture :was allowedetoafstratif y, l the oilfinsoluble Ymaterials z were withdrawn and |.the freflned hydrocarbons werefineutralizved, f washed -an'd 1dried. One hundrediseventeenapartswfga1-kylated product were obtained, thegpropentiesfof -Vwhich along withthoseofthe chargeiare; given i The method dened in "claim 2 wherein theLalcohorsa branchedchain'aloohol"containingat lleast Y10 carbonatoms. vl' y L tlfThe method of 'jalkylating `hydrocatfbons whichcomrises'treating a hydrocarbon joharge boiling above about 400 F,containing'a'substam 'tial proportonof naphthenic 'constituents tolreduce thearomatic t'contentithereofk soV thatr it icontains not morethanf10%'aromaticsandthen reacting `said treatedihydrocarb'onWithiatleastia substantially*equimolar 'quantity of analiphajtc alcohol.containing atleast 8- carbon V=-'at'o1ns; pier roleculeiunderalkylating conditions in the pre'sfence of acatalyst 'of thewaterVabsobingtype';

' JRICHARDM'SfVSE:

